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Letters Pate/nt No. 101,217, dated .Ma-rch 29, '1870i Mone or cUsHIoNING STEAM-Pls'rons.

l The Schedule' referred to in these Letters Patentand making part of the same.

Toll whom mag/ concern Be it known that I, GEORGE F. BLAKE, of the city o Boston, in' the State of Massachusetts. have ire-7` vented afnewand useful 'Cushionng stemt-Piston, applicabletodrilliug-machiues and other percnssive enginery; and 'I do hereby declare the following to be a full andz correct description of the same, reference being -had tothe accompanying drawings, in which- `Figurel is a longitudinal central section of a steamcylinder with my improved cushioning piston applied.

The object'of thisinveutiou is to obtain' from a steam-piston a powerful stroke, free from shockor jar, hyprovidinga' gradual-.`andeffectual cushion for the piston, which, while relieving the shock, shall by its4 elastic impulse increase theelfect-ive force of the blow.

The invention consists of a hollow'pistonplaced. in a steam-cylinder and provided with a solid piston and with devices for cushioning ,said solid pistou oncon- .fined steam at both ends of its stroke, .all as hereinafter more particularly set forth.

To enable others to make and use my'cushioning pist-on, I willproceed to describe its construction and operation. l

The steam-cylinder, marked APAZ in the drawing, is of ordinary construction, and takes steam and exhausts in, the usual way. In this cylinderis placed. the hollow piston B, having the heads H I bolted to it, as shown. In-this piston B works the 4solid piston O on the end 0f piston-rod F, which passes through head H and out through head .P of the main cylinder.

. In the head H' is port J, covered on the inside by `the spring-valve K and the port L, which is open except when the piston C fcomes. over its inner opening at the latter part of its stroke. i

In the head I is port E, covered on. the inside by spring-valve D and p ort M, which is open except when the piston C comesover its inner opening at the latter part of its upper or forward stroke.

To the head I'isattached the -main piston-rod G, which passes thronghthe head N of the steamc -ylin der.

Pinso 1),.placed, respectively, in the heads H and I of piston B,.limit in either direction the stroke of piston O, preventing it frompassing entirely over ports L and M, thereby regulating the-exhaust from hollow` pistou B.

- The drill or hammer to be operated is attached to the end of pistonrod F.

4Thel steam-cylinder is represented iu the drawing'in a horizontal position, but it maybe vertical or at any .desired .ngle.

The operatiolvl is as follows:

Steam `being admitted into thel cylinder at the end A1, drives piston'` B to the other end of the cylinder, At .the same .time, lifting valvev K, it passes-through port J into the interior of piston B, and drives piston C to the forward or upper part of that cylinder, exhausting through port On the reverse stroke the cylinder takes steam at the end A2, and drives the piston B to the opposite end. At the same time the stcam, lifting valve I), enters the piston B through port' lil, and drives piston O to the lower or rear end of the piston B, exhausting through port L.

It is at the end of the rearward or downward stroke of the piston that the blow of the drill, hammer, or other pcrcns'sive tool attached to pistonrod F, is given. At the moment when the blow takes place the piston C is cushioned on compressed steam in the forward end of piston B. This steam gradually exhausts through port M until the'piston G'comes over that port and closes it, when further exhaust is arrested, and the piston cushions on steam compressed and confined in the space between portMand the forward cylinder-head I, thus giving the full pressure of the I area of the steam-cylinder upon the rod'F, at the-end of its stroke, and greatly increasing by the elastic reaction the effectiveness of the blow.

The rods o p limit the endward motion of the piston G, preventing it from passing entirely over and uncovering ports L and M, thereby regulating the exhaust from cylinder B, by keeping vthose ports, respectively, closed when steam is entering at the opposite end of piston B.

Having thus fully described my invention,

What I claim, and desire to secure by Letters Patent, is-

1. The hollow piston B, constructed as described, and working inside a steam-cylinder, as set forth.

X2. The combination and arrangement of the piston B and piston C in the manner specified. 3. The ports E J, valves D K, and ports L M, arranged for conjoint operation with the pistons Band C, in the manner set forth.

I4. A steam-drill, hammer, or percussive engine, in

Witnesses:

B. E. Panni', SAML. W. (luenen, Jr.

eno. F. BLAKE. 

